### Please describe the problem.

Hi,

I'm trying to sync some files to my Android phone using the adb special remote.

Of course, I have a complicated 'wanted' expression: I want new files matching a query be exported automatically on 'sync' and files added on the phone be imported automatically. I also want the files I manually export to the phone to stay where they are.

I'm still debugging my 'wanted' expression,
I run 'git annex sync --content',
notice it isn't syncing the right files,
ctrl+C.

My worktree is left in a weird state: All the files are moved or removed.
It seems git-annex made the worktree into the desired shape for syncing. However, it did that with my main worktree, which is annoying.

To recover from that, 'git reset --hard' works but I also need to do 'git add' then 'git annex fix'.

Is here a reason to use the main worktree instead of a temporary directory to do that ?

Also, it makes a branch 'android/master' which seems weird. First, it doesn't look like 'master' at all, a cryptic name would be better.
This branch isn't supposed to be pushed anywhere and generates tons of conflicts every time, I don't think it should do a branch at all.
Why not rebuild the desired tree into a temporary directory without storing it in git in any way ?

### What steps will reproduce the problem?

Have an 'adb' remote with 'annex-tracking-branch' set to a subdirectory, 'master:subdirectory'.
Kill the process while it is syncing files.

### What version of git-annex are you using? On what operating system?

git-annex version: 10.20220504
Android Debug Bridge version 1.0.41 (31.0.3p1-android-tools)

### Have you had any luck using git-annex before? (Sometimes we get tired of reading bug reports all day and a lil' positive end note does wonders)

I've been using git-annex for a year and it has been awesome for me ! I'm trusting it more and more and that's why I'm trying new things with it.

Thanks a lot for the awesome work !
